SpaceX’s Falcon 9 rocket stands at its new East Coast base, Kennedy Space Center Launch Complex 39-A, ready for a Saturday trip into orbit. The launchpad is the site of former Apollo and space shuttle launches. Photo courtesy SpaceX

Saturday morning’s planned launch will be SpaceX’s first from Florida since a devastating rocket explosion at a neighboring pad last summer. The accident prompted SpaceX to whip 39A into shape sooner than anticipated under its lease with NASA. The pad wrecked in the Sept. 1 accident remains unusable.

Here are five things you need to know about historic Launch Complex 39A at Kennedy Space Center:

Big beginnings

NASA built 39A, as it’s commonly known, in the mid-1960s for the monstrous Saturn V moon rockets. It was first used in 1967 for an unmanned test flight, followed by another early the next year. Next came the astronauts, with Apollo 8 soaring to the moon right before Christmas 1968. SpaceX chief Musk noted late last week via Instagram, “We are honored to be allowed to use it.”

Show-stopping acts

The crescendo came on July 16, 1969, as Apollo 11’s Neil Armstrong, Buzz Aldrin and Michael Collins embarked on the first manned moon landing. All six Apollo moon-landings originated from here, as did close-call Apollo 13. Columbia made the first space shuttle flight from this pad on April 12, 1981, while Atlantis closed out the program from the same spot on July 8, 2011.

Frequent flier

This will be the 95th rocket launch from 39A. It was the departure point for 82 space shuttle flights and 11 Apollo missions, as well as the unmanned 1973 launch of Skylab, NASA’s original space station. One flight resulted in casualties. As Columbia lifted off on Jan. 16, 2003, foam insulation from the external fuel tank broke off and gouged the left wing. Columbia and its crew were lost 16 days later during re-entry.

SpaceX takeover

SpaceX signed a 20-year lease with NASA in 2014, beating out another tech billionaire’s rocket company, Jeff Bezos’ Blue Origin. Renovation work was accelerated after SpaceX’s Sept. 1 rocket explosion a few miles away at Launch Complex 40 on Air Force property. The accident occurred during fueling for a prelaunch test. It is from pad 39A that SpaceX plans to launch Falcon rockets with space station-bound astronauts for NASA as early as next year. The company also might send spacecraft and, ultimately, crews to Mars from this location as well.

Lesser-known twin

Just a mile to the north, Launch Complex 39B is the lesser-known, lesser-used twin. Apollo 10 christened 39B in 1969. In the shuttle era, Challenger inaugurated the pad on Jan. 28, 1986. The doomed flight with schoolteacher Christa McAuliffe lasted 73 seconds. In all, 53 shuttle missions began from this pad, for a total of 59 launches of all types. It was last used in 2009 for an unmanned test flight of NASA’s Ares rocket, canceled soon afterward. NASA is transforming 39B for its yet-to-fly Space Launch System megarocket, intended to send astronauts beyond low-Earth orbit.